Coining presses



June 9 H. D. CHALLEN ETAL 3,191,525

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' R Rm )5 Amman 2pm Httwrnevs June 29, 1965 CHALLEN ETAL 3,191,525

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- Invem'b owrs M R R9 United States Patent 3,191,525 COlNlNG PRESSESHenry Denis Challen, Birmingham, and Denis Ralph Cooper, Surrey,England, assignors to Taylor & Challen Limited, Birmingham, England, aBritish company Filed June 12, 1963, Ser. No. 287,435 Claims priority,application Great Britain, June 15, 1962,

4 Claims. (Cl. 101-4) This invention relates to coining presses, that isto say, presses of the kind in which .a blank or workpiece is squeezedin a confined space between dies to impress on its surfaces the shape ofpatterns carried in the surfaces of the dies. Such presses are normallyused for applying the impressions to the faces of coins and medals butthey can be used for other purposes.

Although ordinary stamping and forging presses frequently have multipledies it has hitherto been usual for coining presses to have only singledies because, in contrast to ordinary presses, coining presses have toapply a very closely controlled blow to the blank and it is normallyimpossible to ensure that two or more pairs of dies situated indifferent areas of the bed of the press strike exactly equal blows.Furthermore any variations in the thickness of the blanks will lead tovariations in the depth of the impressions between one blank andanother.

According to the invention this difficulty is overcome by providing amultiple die coining press in which either the upper or the lower diesare all mounted together in a carrier which can rock to allow the diesto align themselves automatically in a manner such as to distribute theforce evenly between the dies. In this way the blanks receive equalblows even if the thicknesses of the blanks vary or if one die is setslightly higher or lower than another.

According to a further important feature of the invention the carrier isarranged to rock about a point which is in the plane of contact of thedies and is at the mean centre of the dies. This can be achieved byproviding the carrier with a convex part-spherical or part-cylindersurface having this point as its centre or axis of curvature, and thecarrier is received in a concave surface of the same shape.

The invention is preferably applied to the upper dies, the carrier beingthen mounted in the moving slide. In a preferred embodiment there areonly two pairs of dies, side by side, and the axis of curvature of thesurfaces passes perpendicularly through the midpoint of a line joiningthe faces of the two dies. The two upperdies are held rigidly in thecarrier and the upper convex cylindrical surface of the carrier engagesa concave cylindrical surface in the underside of the slide or platen ofthe press. The carrier is held resiliently against this surface byscrews with helical coil compression springs under their heads.

The carrier may also include means for adjusting the positions of thedies horizontally in two mutually perpendicular directions to registerthe upper dies accurately with the lower ones.

The invention will now be further described by way of example withreference to the accompanying drawings, in which:

FIGURE 1 is an elevation of a part of the slide and bed of a press,partly sectioned on a plane containing the axes of the dies;

FIGURE 2 is a partly sectioned elevation of the slide looking from theleft in FIGURE 1;

FIGURE 3 is an inverted plan View of the slide carrying the upper dies;and

FIGURE 4 is a section on the line 44 in FIGURE 1, with the lower diesomitted.

The arrangement illustrated in the drawings employs only two pairs ofdies and so it is sufiicient for the rocking movement provided by theinvention to be about an axis, rather than about a point. Referringfirst to FIGURES 1 and 2, a slide member 1 is dovetailed to thevertically reciprocating slide (not shown) of the press. Its underside 2is of part-cylindrical shape, the axis of curvature of the surface beingin the plane of contact of the pairs of dies and perpendicular to aplane containing the axes of the two dies, midway between those twoaxes.

A carrier in the form of a block 3 having an upper convexpart-cylindrical surface mating with the concave surface of the member 1is secured against the underside of that member by a pair of set-screws4 each of which is screwed into the member 1 whilst its head is receivedin a counterbore in the block 3, and there is a helical coil compressionspring 5 under the head of each screw. The screws 4 thus hold the block3 against the member 1 but allow a limited rocking movement about theaxis of the mating curved surfaces.

A slide 6 has a dovetail engagement with the block 3 allowing relativehorizontal adjustment of the slide on the block. The adjusting movementis effected by a screw 7 carried in a bracket 8 (FIGURE 2) on the slide6. Screws 9 pressing on gibs 10 allow the adjustment to be clamped, andby loosening the screws on one side whilst tightening those on the otherone can also adjust the slide horizontally in a direction perpendicularto the direction of the dovetail surfaces.

In the underside of the slide 6 there are formed two recesses withpart-spherical seats 11 receiving the backing members 12 of the twoupper dies 13. In practice the seats 11 are formed in separate inserts6a in the slide 6 rather than in the material of the slide itself. Thecentre of curvature of each part-spherical seat 11 coincides with thecentre of the face of the associated die.

Each die 13 is clamped in place in the slide 6 by three dogs 14 spacedapart and held against the slide by screws 15. The dogs are so arrangedthat the clamping thrust of each is radial with respect to the sphericalseat allowing adjustment of the tilt of the die 13 in the slide 6 byappropriate adjustment of the three screws. FIGURE 3 shows how theadjacent dogs of the two dies are cut away to clear each other, allowingthe sets of dies to be mounted with their axes as close together aspossible.

The bottom dies, shown at 16, are mounted non-adjustably on the bedmember of the press. Therefore all alignment of the pairs of dies ismade, in the particular embodiment shown, by adjustment of the upperdies 13. To facilitate the setting up of the dies there is a locationplate which has been omitted from FIGURE 1 for clarity but is shown at17 in FIGURE 2 and in the right-hand half of FIGURE 3. This is locatedwith respect to the slide 6 by dowel pins 18 (FIGURE 2) and held byscrews 19, and it has apertures which just fit the ends of the upperdies 13 and hold them at exactly the correct relative spacing. It isused as a jig during setting up and then removed.

The lower dies are capable of vertical movement by means not shown, forejection of the coins after striking, but are accurately locatedlaterally by collars 20 fitting around them.

It will be appreciated that any variation in the depth of the impressionproduced between one side of the blank and the other can be corrected bytilting the die 13 in its spherical seat 11. Likewise any lack ofconcentricity between the impressions on the upper and lower faces ofthe blank is corrected by horizontal adjustment of the slide 6 withrespect to the block 3.

Hitherto it has been difiicult or impossible to make coining presseswith more than one pair of dies. However, by the provision of the curvedsurface 2 we allow slight tilting of the slide 6 (together with theblock 3) about a horizontal axis midway between the faces of the 3 twopairs of dies. Consequently the dies are self-aligning and equal blowsareproduced on the two blanks at each stroke, even though the blank inone pair of dies may be very slightly thicker than that in the otherpair.

Although only two pairs of dies are shown in the embodiment described,it would be possible within the scope of the invention to use threepairs, and the surface 2 would then be part-spherical instead ofpart-cylindrical, with its centre of curvature at the centre of anequilateral triangle formed by the axes of the three pairs of dies.

, Furthermore it would be possible to mount the lower dies rather thanthe upper ones in the manner according to the invention.

We claim:

1. A multiple die coining press comprising a slide member reciprocablelinearly towards and away from a bed member, a carrier mounted on saidslide member, mutually opposed engaging surfaceson said slide member andsaid carrier, said surfaces having an arcuate cross-section,

' Imeans acting between said slide member and said carrier resilientlyurging said surfaces into mutual contact, a plurality of coining diesmounted on said carrier with die faces arranged substantially in acommon plane and sym metrically about a point in said plane, said pointdetermining the centre of curvature of said arcuate cross-section, aplurality of dies mounted on said bed member and disposed to mate withsaid slide member, means for individually adjusting each die of one ofsaid pluralities to enable tiltable adjustment of the face of eachrelative to the face of itsmating die, and clamping means forsecurrelative to its mating die.

2. A multiple die coining press as set forth in claim 1 wherein theadjustable dies are mounted on said carrier, a part-spherical seatingsurface associated with each of the adjustable mounted dies, acomplementary shaped seating surface in said carrier for receiving eachof said die seating surfaces, the common center of curvature ofseatingsurfaces of each die being at the center of the die a0 ing eachadjustably mounted die in its adjusted position A face, said clampingmeans fixedly engaging said seating surfaces in mutual contact.

3. A multiple die coining press comprising a slide member reciprocablelinearly towards and away from a bed member, a carrier mounted on saidslide member, mutually opposed, engaging, part cylindrical surfaces onsaid slide member and said carrier, means acting between said carrierandsaid slide member resiliently urging said surfaces into mutual Contact,a pair of coining dies'mounted on said carrier-with die faces arrangedsubstantially in a common plane,'an'axis of'curvature of saidpart-cylindrical'surfaces lying in said plane and bisecting at rightangles the line joining the centres of said die faces, a second pair ofdies mounted on said bed member and disposed to mate with saidcarrier-mounted dies on movement of said slide member, means forindividually adjusting each of one pair of dies to enable tiltableadjustment of the face of each, with respect to the face of its matingdie, and clamping means for securing each adjustably mounted die in adesired disposition relative to its mating die.

4. A multiple die coining press as set forth in claim 3 wherein saidadjustable pair of dies are mounted 'on the carriena part-sphericalseating surface associated with each of said adjustable dies, acomplementaryshaped seating surface in said carrier for receivi ng eachof said die seating surfaces, the common centre of curvature of saidseating surfaces of each die being at the centre-of the die face, saidclamping means fixedly engaging said seating surfaces in mutual contact.

References Cited by the Examiner UNITED STATES PATENTS 21,473 9/58 Storm'101 4 3,063,664 11/62; Kahlen 101-28 FOREIGN PATENTS 525,628 5/31Germany.

WILLIAM B. PENN, Primary Examiner.

1. A MULTIPLE DIE COINING PRESS COMPRISING A SLIDE MEMBER RECIPROCABLELINEARLY TOWARDS AND AWAY FROM A BED MEMBER, A CARRIER MOUNTED ON SAIDSLIDE MEMBER, MUTUALLY OPPOSED ENGAGING SURFACES ON SAID SLIDE MEMBERAND SAID CARRIER, SAID SURFACES HAVING AN ARCUATE CROSS-SECTION, MEANSACTING BETWEEN SAID SLIDE MEMBER AND SAID CARRIER RESILIENTLY URGINGSAID SURFACES INTO MUTUAL CONTACT, A PLURALITY OF COINING DIES MOUNTEDON SAID CARRIER WITH DIE FACES ARRANGED SUBSTANTIALLY IN A COMMON PLANEAND SYMMETRICALLY ABOUT A POINT IN SAID PLANE, SAID POINT DETERMININGTHE CENTRE OF CURVATURE OF SAID ARCUATE CROSS-SECTION, A PLURALITY OFDIES MOUNTED ON SAID BED MEMBER AND DISPOSED TO MATE WITH SAID SLIDEMEMBER, MEANS FOR INDIVIDUALLY ADJUSTING EACH DIE OF ONE OF SAIDPLURALITIES TO ANABLE TILTABLE ADJUSTMENT OF THE FACE OF EACH RELATIVETO THE FACE OF ITS MATING DIE, AND CLAMPING MEANS FOR SECUR-